(1) Field of the Invention
The invention relates to an actuating mechanism for a vent door and more particularly to an actuating mechanism for a vent door in an aircraft door that provides for the locking of the aircraft door while opening and closing said vent door.
(2) Description of Related Art
A vent door is typically used on the passenger doors of commercial aircraft to allow the pressure inside the aircraft to be equalized with the pressure on the outside of the aircraft after the aircraft lands. For said purpose the doors of aircrafts are often provided with vent-latch interlock assemblies. A typical vent-latch interlock assembly includes a small pressure vent door that is seated in an opening formed in the aircraft cabin door. A drive linkage is connected between the pressure vent door and a latch assembly that controls the opening, closing, and locking of the aircraft cabin door. Vent doors opening and closing mechanism are normally driven by the door lifting mechanism. The drive linkage is arranged so that it will not close the pressure vent door until the associated aircraft cabin door is latched and locked. Consequently, in the event the aircraft cabin door is not properly closed, the open pressure vent door prevents the aircraft from being pressurized, thus requiring aircraft personnel to take note that there is a problem with the cabin door that requires attention. The aircraft will not take off, when the cabin is not pressurized. Moreover, a typical drive linkage is arranged so that, before the latch assembly is actuated to open the aircraft cabin door, the pressure vent door is initially opened. The pressure vent door and the drive linkage are further constructed so that, when the aircraft's cabin pressure is greater than the ambient pressure, the pressure vent door will not open, and the drive linkage will not move. Since the drive linkage is integrally connected to the latch assembly, this “lock-out” of the drive linkage prevents the actuation of the latch assembly and the unlocking and thus prevents unintended opening of the aircraft door. Thus, a pressure vent door assembly is well-suited for installation to an aircraft cabin door to prevent the door from being opened while the aircraft is in pressurized flight.
The document U.S. Pat. No. 5,305,969 A discloses a latch lock mechanism for opening and closing a translating motion-type aircraft door. The latch lock mechanism includes a latch shaft that is mounted to the door and rotated by a lift lock mechanism with a lift lock cam rotated by a handle shaft that is actuated by a handle. When the handle is rotated, the lift lock cam is similarly rotated so as to cause the upward movement of the door drive linkage in the rotation of the latch shaft to allow the door to clear fixed fuselage stop tabs so that the door can be moved to an open position. An auxiliary latch-hold up cam mechanism forces the door open in the event the latch shaft and associated components fail. A pressure vent door is selectively opened by an associated opener assembly connected to the handle shaft. In the event an attempt is made to open the door while the aircraft is in flight, the pressure vent door opener assembly locks out so as to inhibit movement of the handle shaft that would actuate the latch shaft and open the door. The pressure vent door opener assembly and the link to block the handle shaft form a fairly complex system.
Commercial cargo aircraft provide unique concerns and design considerations over passenger aircraft in that cargo aircrafts provide a large cargo door provided in the side of the fuselage. These cargo doors typically have their own latching mechanisms that are not tied into a vent-latch system. Since the cargo doors of cargo aircraft typically do not contain windows or openings therein, a vent-latch assembly similar to those provided in cabin doors of passenger aircraft cannot be installed within the cargo doors. In addition, due to the size of the cargo doors and the loads that the cargo aircraft carry, the cargo doors often require a secondary locking system or backup locking mechanism to prevent the cargo door from unwanted opening.
The document U.S. Pat. No. 6,454,210 B1 discloses an aircraft vent and cargo door locking mechanism for ensuring the opening, closing, and locking of a cargo door in a cargo door opening formed in an aircraft fuselage. A latch assembly latches the cargo door to the fuselage, and the latch assembly moves between a latched position, wherein the cargo door is closed, and an unlatched position, wherein the cargo door may be opened. A locking assembly locks the latch assembly by moving between a locked position, wherein the latch assembly is maintained in the latched position, and an unlocked position, wherein the latch assembly may move to the unlatched position. A blocker provides a secondary locking mechanism by being slidable connected to the cargo door for movement between a blocked position, wherein the blocker engages and prohibits the locking and latch assemblies from moving to the unlocked and unlatched positions, respectively, and an unblocked position, wherein the blocker is disengaged from the locking and latch assemblies allowing the blocking and latch assemblies to move to the unlocked and unlatched positions, respectively. An actuator is operatively connected to the blocker for actuating the blocker between the blocked and unblocked positions. A vent door is mounted adjacent an opening provided in the aircraft fuselage wherein the opening and the vent door are remote from the cargo door. The actuator is operatively connected to the vent door for actuating the vent door between a vent door closed position and a vent door open position simultaneously with the actuation of the blocker. The pressure vent door and the drive linkage are further configured so that, in the event that the ambient pressure is substantially greater than the aircraft cabin pressure, the pressure vent door will open. This allows air to bleed into the aircraft to reduce the pressure differential between the inside of the aircraft and the ambient environment. The minimization of this pressure differential reduces the force imposed on the aircraft by the surrounding atmosphere. The pressure vent door and the drive linkage form a fairly complex system.